Note: I have confirmed with Dark_Shikari on #x264 that 2-pass is fully
functional at this time. The goals between CRF and 2-pass are
different. CRF allows you to specify an average quality setting for
your file regardless of the resulting size. 2-pass is more so used when
you want to keep the resulting file at a designated approximate size.
-Mishehu
On 02/20/2010 10:17 AM, Phil Ehrens wrote:
Andrew Church wrote:
Just as an addendum (though I think it's been mentioned on this list
before), PSNR isn't always a good measurement of visual quality, so take
these results with a grain of salt. Lower PSNR generally means lower
visual quality, but depending on the actual image data, deliberate
"errors" such as averaging pixels can help the brain fill in the missing
detail on its own, causing the image to look better to a human viewer.
This is a very important point! Depending upon the source,
a significantly lower PSNR can look dramatically better -
When transcoding from VHS source, for example. PSNR is
mostly useful for things like determining whether 2-pass
encoding in x264 works or not ;^)
